In a driving circuitry of a liquid crystal display panel, the amplitude of a differential data signal outputted by a timing controller Tcon to a source driver is constant. However, due to layout, temperature, different load images, or the like, the amplitudes of the differential data signals in different groups arrived at the source driver are different, and the reception capacity of the source driver is different in different conditions, thus the requirement on the eye diagram amplitude of the received differential data signal varies with different conditions. If the eye diagram amplitude is set very large to meet the display requirement, the power consumption is increased, and if the eye diagram amplitude is set just large enough to meet the requirement, there is a risk of abnormal display in different conditions.